A Computational Study for Graphene-Based Metasurface Polarizer for Far Infrared Frequency Spectrum–Based Application

Abstract

A tunable silica-graphene-gold composited structure that operates in the infrared frequency range is proposed, and numerical results are presented. The polarization impact of the structure is studied throughout the whole frequency spectrum, which spans from 1 to 30 THz. External biasing can be applied to tune the single-layered graphene sheet’s fermi energy/chemical potential. Several performance indicators, including variations in phase over input and output port, differences in phase for the different polarization, polarization conversion rate, effective refractive indices for metasurface behavior, and reflectance, are used to represent the reaction of the polarizer. To evaluate whether or not linear polarization can be converted to circular polarization, we have investigated a polarizer structure based on graphene in co-polarization and cross-polarization input incident scenarios. Additionally, it exhibits an effective refractive index response, which may be utilized to evaluate the metasurface behavior of the polarizer across the frequency range of 1 to 30 THz. It has been seen that there is a correlation between the polarization amplitude and the Fermi energy/chemical potential of the graphene sheet. The maximum variation in the amplitude of the reflected light was up to 90%, which is attained through the proposed design. This structure is also stable for the wide oblique incident angle up to 80°. The suggested polarizer structure results can be utilized in constructing various electro-optical structures that function in the lower terahertz band.